Looking at the categories and the poll results I see a problem...
Auto oil - it's a problem. Don't use it in a cycle engine.
Back in the day it was fine to use in a cycle, but not anymore. Changes in regulations forced the oil industry to reduce the amounts of Zinc and Phosphorus (ZDDP) in oils designed for passenger cars. That in turn forced the widespread use of roller lifters. Low levels of ZDDP are only adequate for roller (non-solid) valvetrains.
ZDDP is sacrificial in the event that high pressure areas like cams/rockers aren't getting adequate oil quickly enough, and galling could occur. That can happen in any engine with a non-roller valvetrain like a cycle engine.
The inexpensive answer are diesel oils like Shell Rotella, which have safe levels. Cycle-specific oil have at least the same levels as Rotella, and often higher.
One misconception about auto oils is that they all contain "Friction Modifiers" that can make the wet clutch slip - so that's why they shouldn't be used in cycle engine. That's really not much of an issue, as only oils in the 30-grade and below have them anyway.
The REAL issue is the inadequate ZDDP levels.
Just use a diesel (EDIT: or motorcycle specific) oil and you are good.
Last edited by jkv357; 4-21-2018 at 10:35 AM.